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Madsing

Using LCD displays on my Yukari layout

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Madsing

As soon as I started designing my layout, I wanted to use small LCD displays to model not only giant advertisement screens on city buildings, but also train schedule announcement monitors at train stations. Five years ago, nothing interesting was available. We could only find large, green LCD displays not suitable for n gauge. Then, suddenly, probably because of the development of smart watches, many small one- or two-inch high-resolution color displays became available. I read the other posts on this forum (check OLED Building Signs started by mrp in Scenery Techniques & Inspirational Layouts) and at the beginning of 2018, I ordered a few different models for testing.

 

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I ended up using two models for the Shin-Yukari station.

 

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First, I tested this model. Search for "IPS 0.96 inch 7P SPI HD 65K Full Color TFT LCD Module ST7735 Drive IC 80*160" on AliExpress to buy it.

Its shape is not typical. The display area is 10.8 x 21.696mm for a resolution of 188 DPI (dots per inch). Not bad.

  • 10.8 mm / 80 pixels = 0.135 mm/pixel
  • 80 pixels / 10.8 mm = 7.4 pixels/mm = 188 DPI

 

I wanted to use it to display train schedules at the station, but at that resolution the characters were a bit too large. Also, as the connections are on the side of the display, I would have had to place it against a wall. Not ideal. So I decided to use that display at the window of the Uniqlo shop. I placed two, vertically, with only the bottom of the display visible and the connector going through the ceiling. Perfect. I managed to detach the flat panel from the PCB. It’s difficult, but possible. Be extra careful. The display is very thin, just 1 mm. Nice.

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The display requires 3.3 volt power supply and signalling. The Arduino Nano has a 5V to 3.3V converter that I used to supply power to the display. I used resistors to lower the voltage of the 5 volt signals of the Arduino. It works, but using a voltage convert would have been smarter. They are readily available from AliExpress. That’s what I did for the following project (see below).

 

The Arduino Nano does not have enough memory to store all the pictures of the Uniqlo movie, so I stored them in an SD card.

 

For the software, I used the Adafruit_ST7735 library. It provides a bitmap transfer function that I used to transfer the images repeatedly in sequence from the SD card to the display.

 

Things I learned for next time:

  • Choose a micro-controller with 3.3 volt signalling if possible
  • Choose a model with more memory, like the Arduino Mega or the ESP32

 

A couple of months later, this display became available from AliExpress: "High Definition 1.3 Inch IPS TFT Display IPS LCD Screen 1.3 inch 3.3V ST7789 IPS Display Screen"

  • Display Area: 23.4*23.4mm
  • 23.4 mm / 240 pixels = 0.0975 mm/pixel
  • 240 pixels / 23.4 mm = 10.2 pixels/mm = 261 DPI
  • Tested ok with Arduino Nano and Mega, and hardware-specific library for ST7789 (without CS pin)

 

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Its resolution is even higher, perfect for the train schedule display. The integration proved very difficult as it didn’t work with the default ST7789 libraries available for the Arduino. The reason is that the CS (Chip Select) pin from the flat panel is not made available on the connector. I don’t understand why. Anyway, I managed to change the settings of the SPI controller to make it work without that signal.

 

The Arduino does not provide any suitable character generator. Those available are very basic, they do not support Japanese characters and anti-aliasing, so I created all texts as bitmap using Photoshop Elements and transferred them to the Arduino memory.

 

The schedules alternate between English and Japanese. The sequence is programmed in the Arduino memory and is not in any way linked to the trains arriving or leaving the station. That would not be impossible as I use Rocrail to control my trains...

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As for the Uniqlo project, I carefully detached the panels from their PCB. These displays also use 3.3 volt supply and signalling. This time, I used this level converter, with its outputs connected to the four displays in parallel. Look for "IIC I2C Logic Level Converter Bi-Directional Module 5V to 3.3V For Arduino" on AliExpress to buy them. The display power consumption is 35mA at full brightness, 11mA at 25% brightness.

 

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The displays are installed upside down with the connectors at the top, going through the station’s ceiling. There is no visible wire or connector!

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Keith

That looks absolutely amazing.

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JR 500系

That is just way amazing! Way too cool! Thank you for sharing!

 

 

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cteno4

Total awesome sauce Madsing! Really well done and wild skills there doing this mash up!

 

jeff

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maihama eki

Outstanding!

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Madsing

Thank you 😀. I am planing to write more about the software for the Arduino, if anyone is interested I can of course share the code.

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Ochanomizu

Hello Mr Madsing,

 

If there was an award for "Post of the Year" this would win it hands down.

 

Thank you for this amazing insight.

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serotta1972

Wow, that's amazing! 

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Pashina12

Almost makes me wish I was doing a modern setting - this is absolutely stunning!

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Martijn Meerts

That's a lot more electronics than I was expecting 😄

 

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Madsing
2 hours ago, Martijn Meerts said:

That's a lot more electronics than I was expecting 😄

 

 

Granted 😀, I went overboard here. Three Arduinos and six displays for a single building, but it was worth it.

 

IMG_5819.thumb.jpg.e5c8ca6db1ba550e0850a212e6aa10ce.jpg

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Ochanomizu

Hello Mr Madsing,

 

Would you be prepared to provide a shopping list and basic instruction on how to do this project?  In the first instance, I'm interested to know the price.

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Madsing

Hello Ochanomizu,

Yes, sure. Are you more interested in the timetable display, or the Uniqlo display?

Marc

 

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Madsing

Hello Ochanomizu,

This is the shopping list for the timetable display. All prices mentioned are from AliExpress and exclude shipment. This list is for a single display. I chose the Arduino Mega because it has more memory. I chose the Pro version because it is smaller and will more easily fit in the Tomix station's ceiling.

  • Arduino MEGA 2560 PRO Embed CH340G/ATMEGA2560-16AU Chip with male pinheaders Compatible for Arduino Mega2560 (look for "Arduino Mega Pro" on Aliexpress): US$5.39 + shipment
  • 1.3 Inch TFT LCD Screen Display Module 240240 IPS Full Color with 7Pin SPI Interface ST7789 IC Driver for Arduino (look for 240x240 ST7789 LCD display):  US$2.33 + shipment
  • 8 Channel Logic Level Converter Module Bi-Directional Module For Arduino Step Up 3.3V To 5V Module: US$0.91 + shipment (for two pieces)
  • 40pcs/lot 10cm 40P 2.54mm dupont cable jumper wire dupont line female to female: US$0.67 + shipment (for 40 pieces)
  • 5V power supply with USB cable (micro USB)

Marc

 

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Ochanomizu

Hello Madsing,

 

Yes, the timetable display.  Thank you for posting.

 

I don't use Arduino yet.  What basic Arduino parts will I need to run the above?

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Madsing

Hello Ochanomizu,

 

You only need the Arduino and a computer to start. Connect the Arduino to your computer using the USB cable. Download the software (the Arduino IDE from here) and make sure that you can program it. There is a "Getting Started" guide here (and many many others around the web and on Youtube!).

 

Marc

 

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Coromant

Wow!

 

Hello Madsing, i really thanks to sharing the details from Your station. It's very impressiv and it's very ispirate me to upgrade my modules also, i bought the screens  and I already have arduino so i try to build.

 

Thanks,

Best regards,

Coromant

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